Method of making piston rings



Dec. 15, 1925- J. B. WENZEL METHOD OF MAKING PISTON runes Filed Oct. 23, 1924 V v\ u 7 II I A A l i.

INVENTOR. B 75. WW,

ATT EY Patented Dec. 15, 1925. NITED STATES I 1,565,299 PATENT OFFICE.

Jason B. wnnznn, or 121.com, oononano.

ain'rnon or 'MAKING rrsrou RINGS.

Application filed October 23, 1924.. Serial No. 745,535.

method of making piston rings which provides for a ring having an: equal pressure for-its entire circumference, the ring being of the usual split type and the method comprising various steps, the first one being toindent at least one flat face of the ring but preferably both flat faces, thereof, the indentations being'deepest at, the outer edge adjacent to the split portion and deepest at the inner, edge opposite the split portion, the indentations becoming shallower until they are hardly apparent equidistant between the split portion and the point opposite it. v 5

This indenting is for the viding the ring with as much resiliency at the points removed from the split portion,- as at the split portion. The ring is ground on both faces to remove the indentations and is then ready for use. The indenting can be done by pressure means either in the form of a die to come down at asingle blow on the ring or by intermittent blows thereby providing for a hammering, or the indent'a-.

tions can be made by independent blows so that the indentations are formed successively around the ring.

The invention is illustrated in the accompanying drawing in which Figure is a perspective view of a piston ring after it has been indented. Figure 2 shows one,

means of indenting the ring. FigureB, is an enlarged sectional view of the niston-ringf showing the portions that were indented and which are removed by grinding, in dotted outline. Figure 4 is a face view of the ring before it. is ground.

The piston ring is shown at 10 and it is indented on a flat face thereof but preferably on both flat faces. The ring has a split portion 11 and the indentations are deeper on one edge than on the other at the split portion and then the point directly opposite the split portion.

l show at 12 the indentations opposite the split portion, these being deepest on the inner edge and shallower at the outer edze 1 since the purpose of pros of the'piston ring and when they are placed on both faces these indentations-are preferably staggered, that is, the indentations on one face are spaced between the indentations on theother face. The indentations 13, adj acent tothe split portion, are deeper at the outer edge and shallower at the inner edge.

The disposition and arrangement of these indentations is to provide a maximum compression on the inner edge of the ring which has a tendency, ifunder a strain, to force the split portions of the ring further apart.

This is counteracted by the maximum compression on the outer edge of thering as the split portion is approached, which has a tendency to again force the split portion into a circular form. The result is that the ring has equal resiliency and compressive tendency on the walls of the cylinder for its entire circumference. This resiliency is aided by compression on the opposite edges from that-above described to a less extent indentations are much more shallow. V

.These indentations at the split portion and opposite thesplit portion are repeated toward the sides 14- of the ring but become successively shallower as they approach the sides so that at the sides the indentations 15 at'these points are hardly appreciable. It

will be evident that instead of making the and whether this distortion is caused by deeper grooves or grooved closer together is immaterial. 4

As an indication of one form of means for indenting the piston ring, I show in Figure 2 an' anvil 16 and the dies 17, both havin projections 18 to form the indentations in-the ring 10. It will be evident that I may employ any means, if desired, for indenting the parts of thevring successively and not simultaneously and it will be understood in this s ecification that pressure means indicates either the simultaneous indenting of the ring or independent blows on each of the indentations. This indentation of the ring also acts to flatten the ring, that is, make both its fiat faces parallel-and after the indentations the indented portions are removed because the intended even resiliency depends,

on the amount of metal that is distorted by grinding or otherwise and I show in' dotted outline at 19 these indented portions which, however, is distorted below its top and bottom face to give a substantially equal resiliency at all points in its circumference in contrast to'a ring not so treated which would be more resilient at the split' portion than at any other point.

I claim:

l. The method of making piston rings comprising the indenting of the ring on a fiat face thereof, the indenting being done to'a greater extent at the split portion and the point opposite thereto and gradually to a less extent toward the sides of the ring,

that is, the points equidistant between the split portion and the point opposite thereto,

' teena e and then grinding the flat faces so as to move the material to the lowest point of the indentations. 4

2. The method of making piston rings comprising the indenting of the flat faces of the ring, "the indentations being radial and adjacent to the split portion being deepest at the outer edge and shallowest at the inner edge and opposite the split portion being deepest at the inner edge and shallowest at the outer edge, the indentations being successively less pronounced toward the sides of the ring, and then grinding the indented faces to make them flat.

In testimony that I claim the foregoing, l have hereto set my hand, this 18th day" of July, 1924. o

moon. B. wnnznn 

